Why isn't PadKeys showing up in all apps?

Once you've installed PadKeys as a keyboard under device Settings | Keyboard | Keyboards, it should immediately start showing up in every app when you cycle through the options by pressing the Globe key.

HOWEVER, it does not always work this way:

PadKeys will never be shown for password fields, due to security restrictions in iOS.

Individual apps may choose to deliberately disable third-party keyboards for reasons of their own. For example banking apps often disable them everywhere.

Sometimes, due to iOS bugs, some apps don't "get the message" right away that there is a new keyboard available. Ironically it's often Apple's own apps, like Safari and Mail, that have this problem.

In the last case, the apps in question will "wake up" eventually. Sometimes this process can be sped up by killing and restarting the app, or restarting the entire iPad. Other times, despite doing these things, it actually takes a couple of days. Do not despair though: generally once an app "sees" PadKeys for the first time, the problem will not recur.

If you like, we recommend reporting this problem directly to Apple, either via http://www.apple.com/feedback/ipad.html or via their bug reporter if you have a developer account.